This proposal seeks to test a multi-level intervention designed to influence the work culture by incorporating physical activity (PA) and healthier food choices into the workplace routine, based on preliminary results of a :hree-year NCMHD-funded planning grant. Relevance: Population-based obesity control targeting environmental change as well as individual lifestyle change is understudied, particularly in underserved communities. Yet, obesity is increasingly recognized as a major contributor to chronic disease disparities. This proposal targets staff, mostly women of color, who staff agencies that address the needs of low-income and ethnic minority populations. These workers are gatekeepers for their families and communities. Vlobilizing them may help to create the social norm change and political will needed to combat the obesity epidemic. Integrating fitness promoting activities and products into the regular conduct of business is a promising intervention approach arising from our 3-year Community Based Participatory Research (CBPR) planning process. We seek to achieve these goals by using the intervention strategies emerging from this planning phase, such as: conducting walking meetings; implementing brief exercise breaks in staff meetings; adding fruits, vegetables and water as refreshments at work; promoting /improving stairwells,etc. Specifically, we will: 1.. Recruit health and social services organizations in southern and eastern Los Angeles to identify 60 work units of 10-50 staff members each (mean=25 per work unit). Work units may be entire organizations or co- located groups (worksites) within larger organizations. 2. Employ a two-armed, group-randomized, wait list-controlled study design with the work site as the unit of analysis to rigorously evaluate this intervention approach. The primary outcome measure is waist circumference (WC). Secondary outcome measures are body mass index (BMI), cardiorespiratory fitness and blood pressure (BP). Mediating variables include self-reported PA and nutrient intake, 7-day accelerometer count and intensity readings, PA audits, perceived physical activity and nutrition norms, and organizational practices/policies. Data will be collected at baseline, and 6, 12, and 18 months follow-up. 3. Analyze process and outcome data; use results to develop a dissemination plan. The primary hypothesis is that mean WCs in the experimental group will not increase at 12 months compared with significant increases in the control group. The secondary hypothesis is that intervention participants will experience BMI stabilization and improvements in BP and fitness, compared with controls, at 12 months. Similar outcomes are expected at 18 months.